20. Exercise Training and Glycaemic Control

Question 1

what is the effect of 1 year of vigorous aerobic training on the response to an oral glucose test in individuals with mild T2DM?

Answer 1

• Better for handling glucose.

- Insulin has a greater effect at the tissue level. So less is needed to be produced at the pancreas.

Question 2

How could exercise training alter glycaemic control?

Answer 2

1. Delivery of glucose and insulin to the muscle
2. Number of insulin receptors on the myocytes
3. Insulin signalling - adipocytes, fat derivatives (fat uptake, fat oxidation)
4. Amount of GLUT4
5. Glycogen synthase activity

Question 3

Explain how insulin capillary perfusion by nitric oxide production can lead to fat over-supply and endothelial dysfunction

Answer 3

In an endothelial cell, insulin does many things. Insulin when attached to its receptor can stimulate eNOS (endothelial nitric oxide synthase). This can increase the amount of NO in the endothelial cell which then causes vasodilation when diffusing into smooth muscles layer out of the cell. Therefore, the perfusion of the vessel to the muscle is improved. Lipids and lipid derivatives can decrease this - which is bad

Question 4

Explain the metabolic paradox

Answer 4

Intramuscular lipid content vs insulin sensitivity

• Athletes - when you load more fat into a tissue it doesnt become more glucose resistant.
• Intermuscular triglycerols increase lipid derivatives which inhibits insulin signalling in the cell. But in athletes they have lots of mitochondria which causes fatty acid oxidation thus preventing the production of the lipid derivatives

Question 5

Is the ability to take up fat different in T2D sufferers?

Answer 5

Fatty acids can come into the cell and become TAG to react with the mitochondria and cause the cell to release CO2. In T2D they have more fat transporters so there is a greater uptake up of lipids into the cell, making them fatter.

Question 6

Explain how mitochondrial biogenesis improves fat oxidation capacity from training

Answer 6

Mitochondria function can be improved through training. Exercise increases AMPK which increases the amount of transcription factors in the cell. This, when activated, can move and attach to PGC-1a which when switched on can produce mitochondrial transcription factors and produces more and more mitochondria

Question 7

AMPK is activated more through exercise

Answer 7

AMPK increases fatty acid oxidation in the muscle

Question 8

How does regular exercise affect insulin and GLUT 4 translocation?

Answer 8

it enhances the insulin activation of the translocators which increases the uptake if glucose into the cell.
More GLUT4 when your regularly active means an increase in GLUT4 mRNA

Question 9

AMPK - fun facts

Answer 9

Involved in many processes. IF you switch on AMPK you can get an increase of GLUT4. Increase in fat oxidation. Increase in mitochondrial biogenesis. increase in GLUT4 translocation.

Question 10

What are some effect of training on glycaemic control?

Answer 10

Muscle hypertrophy - increase in target tissue
Less inhibition of insulin-induced capillary perfusion
Muscle capillary density - increases exposure to target tissue
The number of insulin receptors and amount of IRS-1 doesn’t appear to change but the ability of them to phosphorylate upon activation is enhanced, which in turn leads to greater insulin-induced PI3 kinase activity..
increased mRNA and protein of GLUT4 transporter
Increases enzymes of glucose storage and oxidation